#!/bin/bash

# @Function
# Find out the highest cpu consumed threads of java, and print the stack of these threads.
#
# @Usage
# $ ./show-busy-java-threads.sh
#
# @author Jerry Lee

readonly PROG=$(basename $0)
readonly -a COMMAND_LINE=("$0""$@")

usage() {
    cat <<EOF
Usage: ${PROG} [OPTION]...
Find out the highest cpu consumed threads of java, and print the stack of these threads.
Example: ${PROG} -c 10

Options:
    -p, --pid find out the highest cpu consumed threads from the specifed java process,
                    default from all java process.
    -c, --count set the thread count to show, default is 5
    -h, --help      display this help and exit
EOF
exit$1
}

readonly ARGS=$(getopt -n "$PROG" -a -o c:p:h -l count:,pid:,help -- "$@")
[ $? -ne 0 ] && usage 1
evalset -- "${ARGS}"

whiletrue; do
case"$1"in
    -c|--count)
        count="$2"
shift 2
        ;;
    -p|--pid)
        pid="$2"
shift 2
        ;;
    -h|--help)
        usage
        ;;
    --)
shift
break
        ;;
esac
done
count=${count:-5}

redEcho() {
    [ -c /dev/stdout ] && {
# if stdout is console, turn on color output.
echo -ne "\033[1;31m"
echo -n "$@"
echo -e "\033[0m"
    } || echo"$@"
}

yellowEcho() {
    [ -c /dev/stdout ] && {
# if stdout is console, turn on color output.
echo -ne "\033[1;33m"
echo -n "$@"
echo -e "\033[0m"
    } || echo"$@"
}

blueEcho() {
    [ -c /dev/stdout ] && {
# if stdout is console, turn on color output.
echo -ne "\033[1;36m"
echo -n "$@"
echo -e "\033[0m"
    } || echo"$@"
}

# Check the existence of jstack command!
if ! which jstack &> /dev/null; then
    [ -z "$JAVA_HOME" ] && {
        redEcho "Error: jstack not found on PATH!"
exit 1
    }
    ! [ -f "$JAVA_HOME/bin/jstack" ] && {
        redEcho "Error: jstack not found on PATH and $JAVA_HOME/bin/jstack file does NOT exists!"
exit 1
    }
    ! [ -x "$JAVA_HOME/bin/jstack" ] && {
        redEcho "Error: jstack not found on PATH and $JAVA_HOME/bin/jstack is NOT executalbe!"
exit 1
    }
export PATH="$JAVA_HOME/bin:$PATH"
fi

readonly uuid=`date +%s`_${RANDOM}_$$

cleanupWhenExit() {
    rm /tmp/${uuid}_* &> /dev/null
}
trap"cleanupWhenExit" EXIT

printStackOfThreads() {
local line
local count=1
while IFS=" "read -a line ; do
local pid=${line[0]}
local threadId=${line[1]}
local threadId0x="0x`printf %x ${threadId}`"
local user=${line[2]}
local pcpu=${line[4]}

local jstackFile=/tmp/${uuid}_${pid}

[ ! -f "${jstackFile}" ] && {
    {
        if [ "${user}" == "${USER}" ]; then
            jstack ${pid} > ${jstackFile}
        else
            if [ $UID == 0 ]; then
                sudo -u ${user} jstack ${pid} > ${jstackFile}
            else
                redEcho "[$((count++))] Fail to jstack Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
                redEcho "User of java process($user) is not current user($USER), need sudo to run again:"
                yellowEcho " sudo ${COMMAND_LINE[@]}"
            echo
            continue
            fi
        fi
    } || {
        redEcho "[$((count++))] Fail to jstack Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
        echo
        rm ${jstackFile}
        continue
    }
}
    blueEcho "[$((count++))] Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user}):"
    sed "/nid=${threadId0x} /,/^$/p" -n ${jstackFile}
    done
}

ps -Leo pid,lwp,user,comm,pcpu --no-headers | {
    [ -z "${pid}" ] &&
    awk '$4=="java"{print $0}' ||
    awk -v "pid=${pid}"'$1==pid,$4=="java"{print $0}'
} | sort -k5 -r -n | head --lines "${count}" | printStackOfThrea